drm: update PCIGART support from CVS

In order to work on FreeBSD the gart needed to use a local mapping
This patch moves the mainline to the new code and aligns some comment
changes

From: Eric Anholt <anholt@freebsd.org>
Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/char/drm/drmP.h b/drivers/char/drm/drmP.h
index a3ad85e..43c49ad 100644
--- a/drivers/char/drm/drmP.h
+++ b/drivers/char/drm/drmP.h
@@ -522,8 +522,9 @@
 typedef struct ati_pcigart_info {
 	int gart_table_location;
 	int is_pcie;
-	unsigned long addr;
+	void *addr;
 	dma_addr_t bus_addr;
+	drm_local_map_t mapping;
 } drm_ati_pcigart_info;
 
 /**